Integrally connected blade-disk units, which are also referred to as ‘blisk’, are used in the manufacture of turbine engines such as gas turbines or aircraft engines, blisk being shorthand for the combination of blade and disk. Such blade-disk units, which constitute a rotor for a corresponding gas turbine or an aircraft engine, are characterized by the fixation of the blades on the disk in integral fashion, e.g., by welding. However, inasmuch as different materials are used for the blades and the disks in the turbine, welding the blades directly to the disk is impossible in such a case, because the welding could cause a corresponding change in, or damage to, the disk or blade material, which would lead to an unacceptable characteristics profile.
For example, forgeable nickel alloys suitable for fusion welding such as Inconel 718, for example, are frequently used in the turbine of aircraft engines; the blade materials, on the other hand, are polycrystalline, directedly solidified or monocrystalline nickel cast alloys having a high γ′ component, which imbues the blade material with the necessary strength. Fusing of the blade material would destroy this structure and therefore have a detrimental effect on the strength of the blade.
It is conventional to use an adaptor between the blade and disk, the adapter being joined to the blade by friction welding, and the adapter subsequently being fixed in place on the disk by fusion welding. However, this is very costly and labor-intensive due to the additional use of the adapter and the required additional welding operations.